Misinformation is a deservedly, regrettably popular topic these days. But separating it from knowledge, ignorance, and mere (less confident) belief requires conceptual line-drawing and poses operational challenges. Conceptually, the questions include the boundaries between misinformation, knowledge, ignorance, and mere belief. Operationally, we trace the relationships between correct, incorrect, and DK responses, on the one hand, and knowledge, misinformation, ignorance, and mere belief, on the other. We argue that most existing “misinformation items” overstate misinformation (and knowledge) and understate ignorance—partly on account of their usual multiple choice format, partly on account of other features. We present a superior measure and apply it to data from several original surveys to examine the prevalence of misinformation and its correlations with party and ideology, among other variables.
